compat: fixes

* fix nixos-option
* use flake-compat for all backward compat concerns
* rebuild devshell after any nix file changes
* reexport system pkgs as legacyPackages
* provide lib flake output
* provide flake lib to nixos configs via `lib.flk`
* clean up flake.nix

.envrc

@@ -1,2 +1,2 @@
-watch_file shell.nix
+watch_file **/*.nix
 use flake || use nix

compat/default.nix

@@ -0,0 +1,13 @@
+let
+  flake = (import
+    (
+      fetchTarball {
+        url = "https://github.com/edolstra/flake-compat/archive/99f1c2157fba4bfe6211a321fd0ee43199025dbf.tar.gz";
+        sha256 = "sha256:0x2jn3vrawwv9xp15674wjz9pixwjyj3j771izayl962zziivbx2";
+      }
+    )
+    {
+      src = ../.;
+    });
+in
+flake

compat/fetch.nix

@@ -1,17 +0,0 @@
-let
-  inherit (builtins)
-    fetchTarball
-    fromJSON
-    readFile
-    ;
-  lockfile = fromJSON (readFile ../flake.lock);
-in
-input:
-let
-  locked = lockfile.nodes."${input}".locked;
-  inherit (locked) rev narHash owner repo;
-in
-fetchTarball {
-  url = "https://github.com/${owner}/${repo}/archive/${rev}.tar.gz";
-  sha256 = narHash;
-}

compat/nixos/default.nix

@@ -0,0 +1,10 @@
+{ ... }:
+let
+  inherit (default.inputs.nixos) lib;
+
+  host = configs.${hostname} or configs.NixOS;
+  configs = default.nixosConfigurations;
+  default = (import ../.).defaultNix;
+  hostname = lib.fileContents /etc/hostname;
+in
+host

compat/nixpkgs.nix

@@ -1,5 +0,0 @@
-let
-  fetch = import ./fetch.nix;
-  nixpkgs = fetch "nixos";
-in
-nixpkgs

configuration.nix

@@ -1,41 +0,0 @@
-# this file is an impure recreation of the flake profile currently deployed
-# based on the systems hostname. The purpose is so tools which do not yet have
-# flake support (e.g `nixos-option`), can work as expected.
-{ lib, ... }:
-let
-  inherit (builtins) attrNames readDir;
-
-  nixpkgs = toString (import ./nixpkgs-compat.nix);
-
-  hostname = lib.fileContents /etc/hostname;
-  host = "/etc/nixos/hosts/${hostname}.nix";
-  config =
-    if (builtins.pathExists host) then
-      [ host ]
-    else
-      [ /etc/nixos/hosts/NixOS.nix ];
-in
-{
-  imports = (import ./modules/list.nix) ++ [
-    "${
-      builtins.fetchTarball
-        "https://github.com/nix-community/home-manager/archive/master.tar.gz"
-      }/nixos"
-    /etc/nixos/profiles/core
-  ] ++ config;
-
-  networking.hostName = hostname;
-  nix.nixPath = [
-    "nixpkgs=${nixpkgs}"
-    "nixos-config=/etc/nixos/configuration.nix"
-    "nixpkgs-overlays=/etc/nixos/overlays"
-  ];
-
-  nixpkgs.overlays =
-    let
-      overlays = map
-        (name: import (./overlays + "/${name}"))
-        (attrNames (readDir ./overlays));
-    in
-    overlays;
-}

default.nix

@@ -1,15 +1,6 @@
 let
-  inherit (flake.inputs.nixos.lib) recurseIntoAttrs mapAttrs;
-  flake = (import
-    (
-      fetchTarball {
-        url = "https://github.com/edolstra/flake-compat/archive/99f1c2157fba4bfe6211a321fd0ee43199025dbf.tar.gz";
-        sha256 = "sha256:0x2jn3vrawwv9xp15674wjz9pixwjyj3j771izayl962zziivbx2";
-      }
-    )
-    {
-      src = ./.;
-    }).defaultNix;
-  recurse = mapAttrs (_: v: recurseIntoAttrs v) flake.packages;
+  inherit (default.inputs.nixos.lib) recurseIntoAttrs;
+
+  default = (import ./compat).defaultNix;
 in
-recurse
+builtins.mapAttrs (_: v: recurseIntoAttrs v) default.packages

flake.nix

@@ -15,48 +15,34 @@
 
   outputs = inputs@{ self, home, nixos, master, flake-utils, nur, devshell, nixos-hardware }:
     let
-      inherit (builtins) attrNames attrValues elem pathExists;
-      inherit (flake-utils.lib) eachDefaultSystem mkApp flattenTreeSystem;
-      inherit (nixos) lib;
-      inherit (lib) recursiveUpdate filterAttrs mapAttrs;
-      inherit (utils) pathsToImportedAttrs genPkgset overlayPaths modules
-        genPackages pkgImport;
-
-      utils = import ./lib/utils.nix { inherit lib; };
+      inherit (builtins) attrValues;
+      inherit (flake-utils.lib) eachDefaultSystem flattenTreeSystem;
+      inherit (nixos.lib) recursiveUpdate;
+      inherit (self.lib) overlays nixosModules genPackages pkgImport;
 
       externOverlays = [ nur.overlay devshell.overlay ];
       externModules = [ home.nixosModules.home-manager ];
 
-      pkgs' = unstable:
-        let
-          override = import ./pkgs/override.nix;
-          overlays = (attrValues self.overlays)
-            ++ externOverlays
-            ++ [ self.overlay (override unstable) ];
-        in
-        pkgImport nixos overlays;
-
-      unstable' = pkgImport master [ ];
-
-      osSystem = "x86_64-linux";
-
       outputs =
         let
-          system = osSystem;
-          unstablePkgs = unstable' system;
-          osPkgs = pkgs' unstablePkgs system;
+          system = "x86_64-linux";
+          pkgs = self.legacyPackages.${system};
         in
         {
+          inherit nixosModules overlays;
+
           nixosConfigurations =
-            import ./hosts (recursiveUpdate inputs {
-              inherit lib osPkgs unstablePkgs utils externModules system;
-            });
+            import ./hosts
+              (recursiveUpdate inputs {
+                inherit pkgs externModules system;
+                inherit (pkgs) lib;
+              });
 
           overlay = import ./pkgs;
 
-          overlays = pathsToImportedAttrs overlayPaths;
-
-          nixosModules = modules;
+          lib = import ./lib {
+            inherit (nixos) lib;
+          };
 
           templates.flk.path = ./.;
 
@@ -69,8 +55,26 @@
       (eachDefaultSystem
         (system:
           let
-            unstablePkgs = unstable' system;
-            pkgs = pkgs' unstablePkgs system;
+            unstable = pkgImport master [ ] system;
+
+            pkgs =
+              let
+                override = import ./pkgs/override.nix;
+                overlays = (attrValues self.overlays)
+                  ++ externOverlays
+                  ++ [
+                  self.overlay
+                  (override unstable)
+                  (final: prev: {
+                    lib = (prev.lib or { }) // {
+                      inherit (nixos.lib) nixosSystem;
+                      flk = self.lib;
+                      utils = flake-utils.lib;
+                    };
+                  })
+                ];
+              in
+              pkgImport nixos overlays system;
 
             packages = flattenTreeSystem system
               (genPackages {
@@ -80,9 +84,11 @@
           {
             inherit packages;
 
-            devShell = import ./shell.nix {
-              inherit pkgs;
+            devShell = import ./shell {
+              inherit pkgs nixos;
             };
+
+            legacyPackages = pkgs;
           }
         )
       )

hosts/default.nix

@@ -3,16 +3,14 @@
 , nixos
 , master
 , nixos-hardware
-, osPkgs
+, pkgs
 , self
 , system
-, unstablePkgs
-, utils
 , externModules
 , ...
 }:
 let
-  inherit (utils) recImport;
+  inherit (lib.flk) recImport;
   inherit (builtins) attrValues removeAttrs;
 
   unstableModules = [ ];
@@ -50,12 +48,11 @@ let
               [
                 "nixos-unstable=${master}"
                 "nixpkgs=${nixos}"
-                "nixos-config=${path}/configuration.nix"
                 "nixpkgs-overlays=${path}/overlays"
                 "home-manager=${home}"
               ];
 
-            nixpkgs.pkgs = osPkgs;
+            nixpkgs = { inherit pkgs; };
 
             nix.registry = {
               master.flake = master;

lib/default.nix

@@ -14,6 +14,7 @@ let
   # Generate an attribute set by mapping a function over a list of values.
   genAttrs' = values: f: listToAttrs (map f values);
 
+  # pkgImport :: Nixpkgs -> Overlays -> System -> Pkgs
   pkgImport = nixpkgs: overlays: system:
     import nixpkgs {
       inherit system overlays;
@@ -23,16 +24,13 @@ let
   # Convert a list to file paths to attribute set
   # that has the filenames stripped of nix extension as keys
   # and imported content of the file as value.
+  #
   pathsToImportedAttrs = paths:
     genAttrs' paths (path: {
       name = removeSuffix ".nix" (baseNameOf path);
       value = import path;
     });
 
-in
-{
-  inherit mapFilterAttrs genAttrs' pkgImport pathsToImportedAttrs;
-
   overlayPaths =
     let
       overlayDir = ../overlays;
@@ -40,6 +38,12 @@ in
     in
     map fullPath (attrNames (readDir overlayDir));
 
+in
+{
+  inherit mapFilterAttrs genAttrs' pkgImport pathsToImportedAttrs;
+
+  overlays = pathsToImportedAttrs overlayPaths;
+
   recImport = { dir, _import ? base: import "${dir}/${base}.nix" }:
     mapFilterAttrs
       (_: v: v != null)
@@ -51,7 +55,7 @@ in
           nameValuePair ("") (null))
       (readDir dir);
 
-  modules =
+  nixosModules =
     let
       # binary cache
       cachix = import ../cachix.nix;

profiles/core/default.nix

@@ -74,6 +74,9 @@ in
           manix "" | grep '^# ' | sed 's/^# \(.*\) (.*/\1/;s/ (.*//;s/^# //' | sk --preview="manix '{}'" | xargs manix
         '';
 
+        # fix nixos-option
+        nixos-option = "nixos-option -I nixpkgs=${toString ../../compat}";
+
         # sudo
         s = ifSudo "sudo -E ";
         si = ifSudo "sudo -i";

shell.nix

@@ -1,92 +1 @@
-let
-  nixpkgs = import ./compat/nixpkgs.nix;
-  fetch = import ./compat/fetch.nix;
-
-  devshell' = fetch "devshell";
-  pkgs' = import devshell' { inherit nixpkgs; };
-in
-{ pkgs ? pkgs', ... }:
-let
-  build = "config.system.build";
-
-  installPkgs = (import "${nixpkgs}/nixos" {
-    configuration = { };
-    system = pkgs.system;
-  }).config.system.build;
-
-  flk = pkgs.writeShellScriptBin "flk" ''
-    if [[ -z "$1" ]]; then
-      echo "Usage: $(basename "$0") [ iso | up | install {host} | {host} [switch|boot|test] ]"
-    elif [[ "$1" == "up" ]]; then
-      mkdir -p up
-      hostname=$(hostname)
-      nixos-generate-config --dir up/$hostname
-      echo \
-      "{
-      imports = [ ../up/$hostname/configuration.nix ];
-    }" > hosts/up-$hostname.nix
-    git add -f up/$hostname
-    git add -f hosts/up-$hostname.nix
-    elif [[ "$1" == "iso" ]]; then
-      nix build $DEVSHELL_ROOT#nixosConfigurations.niximg.${build}.isoImage "${"\${@:2}"}"
-    elif [[ "$1" == "install" ]]; then
-      sudo nixos-install --flake ".#$2" "${"\${@:3}"}"
-    else
-      sudo nixos-rebuild --flake ".#$1" "${"\${@:2}"}"
-    fi
-  '';
-
-  name = "flk";
-in
-pkgs.mkDevShell {
-  inherit name;
-
-  packages = with pkgs; with installPkgs; [
-    git-crypt
-    nixos-install
-    nixos-generate-config
-    nixos-enter
-    pre-commit
-  ];
-
-  env = { inherit name; };
-
-  commands = with pkgs; [
-    {
-      name = nixpkgs-fmt.pname;
-      package = nixpkgs-fmt;
-      help = nixpkgs-fmt.meta.description;
-      category = "linters";
-    }
-    {
-      name = flk.name;
-      help = "Build, deploy, and install nixflk";
-      category = "main";
-      package = flk;
-    }
-    {
-      name = "hooks";
-      help = "install git hooks";
-      command = "pre-commit install";
-    }
-    {
-      name = "grip";
-      help = python38Packages.grip.meta.description;
-      category = "servers";
-      package = python38Packages.grip;
-    }
-    {
-      name = git.pname;
-      help = git.meta.description;
-      category = "vcs";
-      package = git;
-    }
-    {
-      name = "nix";
-      help = nixFlakes.meta.description;
-      category = "main";
-      command = ''${nixFlakes}/bin/nix --option experimental-features "nix-command flakes ca-references" "$@"'';
-    }
-  ];
-
-}
+(import ./compat).shellNix

shell/default.nix

@@ -0,0 +1,89 @@
+{ pkgs ? (import ./compat).defaultNix.legacyPackages."${builtins.currentSystem}"
+, nixos ? (import ./compat).defaultNix.inputs.nixos
+, ...
+}:
+let
+  build = "config.system.build";
+
+  installPkgs = (import "${nixos}/nixos" {
+    configuration = { };
+    system = pkgs.system;
+  }).config.system.build;
+
+  flk = pkgs.writeShellScriptBin "flk" ''
+    if [[ -z "$1" ]]; then
+      echo "Usage: $(basename "$0") [ iso | up | install {host} | {host} [switch|boot|test] ]"
+    elif [[ "$1" == "up" ]]; then
+      mkdir -p up
+      hostname=$(hostname)
+      nixos-generate-config --dir up/$hostname
+      echo \
+      "{
+      imports = [ ../up/$hostname/configuration.nix ];
+    }" > hosts/up-$hostname.nix
+    git add -f up/$hostname
+    git add -f hosts/up-$hostname.nix
+    elif [[ "$1" == "iso" ]]; then
+      nix build $DEVSHELL_ROOT#nixosConfigurations.niximg.${build}.isoImage "${"\${@:2}"}"
+    elif [[ "$1" == "install" ]]; then
+      sudo nixos-install --flake ".#$2" "${"\${@:3}"}"
+    else
+      sudo nixos-rebuild --flake ".#$1" "${"\${@:2}"}"
+    fi
+  '';
+
+  name = "flk";
+in
+pkgs.mkDevShell {
+  inherit name;
+
+  packages = with pkgs; with installPkgs; [
+    git-crypt
+    nixos-install
+    nixos-generate-config
+    nixos-enter
+    nixos-option
+    pre-commit
+  ];
+
+  env = { inherit name; };
+
+  commands = with pkgs; [
+    {
+      name = nixpkgs-fmt.pname;
+      package = nixpkgs-fmt;
+      help = nixpkgs-fmt.meta.description;
+      category = "linters";
+    }
+    {
+      name = flk.name;
+      help = "Build, deploy, and install nixflk";
+      category = "main";
+      package = flk;
+    }
+    {
+      name = "hooks";
+      help = "install git hooks";
+      command = "pre-commit install";
+    }
+    {
+      name = "grip";
+      help = python38Packages.grip.meta.description;
+      category = "servers";
+      package = python38Packages.grip;
+    }
+    {
+      name = git.pname;
+      help = git.meta.description;
+      category = "vcs";
+      package = git;
+    }
+    {
+      name = "nix";
+      help = nixFlakes.meta.description;
+      category = "main";
+      command = ''${nixFlakes}/bin/nix --option experimental-features "nix-command flakes ca-references" "$@"'';
+    }
+  ];
+
+}